This book is based on the teaching discourse given by Kyabje Yongdzin Lop n Tenzin Namdak Rinpoche on The Four Wheels of B n. Found in Zijyi, the long biography of T npa Shenrab Miwoche, the Buddha of Yungdrung B n. This discourse combines the oral translation of the original text with the direct instructions coming from the mind of the Teacher of Teachers - Yongdzin Rinpoche, the most illustrious and erudite B npo master and scholar of our times. Since the teachings contained in this volume form the very foundation for the practice and study of Yungdrung B n, this text will bring benefit to all, from those who are just beginning to take an interest in this most ancient and authentic spiritual tradition to those who have already been studying and practising for many years, as well as to academicians and B npo scholars.